High DPI-aware Tarmac

examples/03-high-dpi/README.md

@@ -0,0 +1,2 @@
+# High DPI Example
+This is an example demonstrating how Tarmac detects high DPI variants of assets and automatically generates code to pick the correct variant.

examples/03-high-dpi/src/assets.lua

@@ -0,0 +1,8 @@
+-- This file was @generated by Tarmac. It is not intended for manual editing.
+return {
+	assets = {
+		hello = "rbxassetid://4967166732",
+		["hello@2x"] = "rbxassetid://4967220902",
+		["hello@3x"] = "rbxassetid://4967220945",
+	},
+}

examples/03-high-dpi/tarmac-manifest.toml

@@ -0,0 +1,14 @@
+[inputs."assets/hello.png"]
+hash = "55ef7fd70ec96da73fa0f09bf530605961cce1a654f02684a1a0b0a6234b06cb"
+id = 4967166732
+packable = false
+
+[inputs."assets/hello@2x.png"]
+hash = "02845c418d2c3abe798d1babeecc2e124dddc4765a840cd03d171f32351be3af"
+id = 4967220902
+packable = false
+
+[inputs."assets/hello@3x.png"]
+hash = "1d075da844e76c9e3ec924c1a7fa8efaedbf35787038063664ef939470d7f57c"
+id = 4967220945
+packable = false

examples/03-high-dpi/tarmac.toml

@@ -0,0 +1,6 @@
+name = "03-high-dpi"
+
+[[inputs]]
+glob = "assets/**/*.png"
+codegen = true
+codegen-path = "src/assets.lua"

src/asset_name.rs

@@ -35,12 +35,6 @@ impl AssetName {
         AssetName(displayed.into())
     }
 
-    /// Spritesheets don't have any canonical name provided by Tarmac's inputs;
-    /// when we upload them, we want to give them a simple dummy name
-    pub fn spritesheet() -> Self {
-        AssetName("spritesheet.png".into())
-    }
-
     #[cfg(test)]
     pub(crate) fn new<S: AsRef<str>>(inner: S) -> Self {
         Self(inner.as_ref().into())

src/codegen.rs

@@ -3,7 +3,7 @@
 //! Tarmac uses a small Lua AST to build up generated code.
 
 use std::{
-    collections::BTreeMap,
+    collections::{BTreeMap, HashMap},
     io::{self, Write},
     path::{self, Path},
 };
@@ -27,22 +27,33 @@ pub fn perform_codegen(output_path: Option<&Path>, inputs: &[&SyncInput]) -> io:
     }
 }
 
+/// Tree used to track and group inputs hierarchically, before turning them into
+/// Lua tables.
+enum GroupedItem<'a> {
+    Folder {
+        children_by_name: BTreeMap<String, GroupedItem<'a>>,
+    },
+    InputGroup {
+        inputs_by_dpi_scale: HashMap<u32, &'a SyncInput>,
+    },
+}
+
 /// Perform codegen for a group of inputs who have `codegen_path` defined.
 ///
 /// We'll build up a Lua file containing nested tables that match the structure
 /// of the input's path with its base path stripped away.
 fn codegen_grouped(output_path: &Path, inputs: &[&SyncInput]) -> io::Result<()> {
-    /// Represents the tree of inputs as we're discovering them.
-    enum Item<'a> {
-        Folder(BTreeMap<&'a str, Item<'a>>),
-        Input(&'a SyncInput),
-    }
-
-    let mut root_folder: BTreeMap<&str, Item<'_>> = BTreeMap::new();
+    let mut root_folder: BTreeMap<String, GroupedItem<'_>> = BTreeMap::new();
 
     // First, collect all of the inputs and group them together into a tree
     // according to their relative paths.
-    for input in inputs {
+    for &input in inputs {
+        // Not all inputs will be marked for codegen. We can eliminate those
+        // right away.
+        if !input.config.codegen {
+            continue;
+        }
+
         // If we can't construct a relative path, there isn't a sensible name
         // that we can use to refer to this input.
         let relative_path = input
@@ -65,69 +76,97 @@ fn codegen_grouped(output_path: &Path, inputs: &[&SyncInput]) -> io::Result<()>
 
         // Navigate down the tree, creating any folder entries that don't exist
         // yet.
-        //
-        // This is basically an in-memory `mkdir -p` followed by `touch`.
         let mut current_dir = &mut root_folder;
         for (i, segment) in segments.iter().enumerate() {
             if i == segments.len() - 1 {
                 // We assume that the last segment of a path must be a file.
 
-                let name = segment.file_stem().unwrap().to_str().unwrap();
-                current_dir.insert(name, Item::Input(input));
+                let name = &input.stem_name;
+
+                let input_group = match current_dir.get_mut(name) {
+                    Some(existing) => existing,
+                    None => {
+                        let input_group = GroupedItem::InputGroup {
+                            inputs_by_dpi_scale: HashMap::new(),
+                        };
+                        current_dir.insert(name.to_owned(), input_group);
+                        current_dir.get_mut(name).unwrap()
+                    }
+                };
+
+                if let GroupedItem::InputGroup {
+                    inputs_by_dpi_scale,
+                } = input_group
+                {
+                    inputs_by_dpi_scale.insert(input.dpi_scale, input);
+                } else {
+                    unreachable!();
+                }
             } else {
-                let name = segment.to_str().unwrap();
+                let name = segment.to_str().unwrap().to_owned();
                 let next_entry = current_dir
                     .entry(name)
-                    .or_insert_with(|| Item::Folder(BTreeMap::new()));
+                    .or_insert_with(|| GroupedItem::Folder {
+                        children_by_name: BTreeMap::new(),
+                    });
 
-                match next_entry {
-                    Item::Folder(next_dir) => {
-                        current_dir = next_dir;
-                    }
-                    Item::Input(_) => {
-                        log::error!(
-                            "A path tried to traverse through a folder as if it were a file: {}",
-                            input.path.display()
-                        );
-                        log::error!("The path segment '{}' is a file because of previous inputs, not a file.", name);
-                        break;
-                    }
+                if let GroupedItem::Folder { children_by_name } = next_entry {
+                    current_dir = children_by_name;
+                } else {
+                    unreachable!();
                 }
             }
         }
     }
 
-    fn build_item(item: &Item<'_>) -> Option<Expression> {
+    fn build_item(item: &GroupedItem<'_>) -> Option<Expression> {
         match item {
-            Item::Folder(children) => {
-                let entries = children
+            GroupedItem::Folder { children_by_name } => {
+                let entries = children_by_name
                     .iter()
-                    .filter_map(|(&name, child)| build_item(child).map(|item| (name.into(), item)))
+                    .filter_map(|(name, child)| build_item(child).map(|item| (name.into(), item)))
                     .collect();
 
                 Some(Expression::table(entries))
             }
-            Item::Input(input) => {
-                if input.config.codegen {
+            GroupedItem::InputGroup {
+                inputs_by_dpi_scale,
+            } => {
+                if inputs_by_dpi_scale.len() == 1 {
+                    // If there is exactly one input in this group, we can
+                    // generate code knowing that there are no high DPI variants
+                    // to choose from.
+
+                    let input = inputs_by_dpi_scale.values().next().unwrap();
+
                     if let Some(id) = input.id {
                         if let Some(slice) = input.slice {
                             let template = UrlAndSliceTemplate { id, slice };
 
-                            return Some(template.to_lua());
+                            Some(template.to_lua())
                         } else {
                             let template = AssetUrlTemplate { id };
 
-                            return Some(template.to_lua());
+                            Some(template.to_lua())
                         }
+                    } else {
+                        None
                     }
-                }
+                } else {
+                    // In this case, we have the same asset in multiple
+                    // different DPI scales. We can generate code to pick
+                    // between them at runtime.
 
-                None
+                    unimplemented!()
+                }
             }
         }
     }
 
-    let root_item = build_item(&Item::Folder(root_folder)).unwrap();
+    let root_item = build_item(&GroupedItem::Folder {
+        children_by_name: root_folder,
+    })
+    .unwrap();
     let ast = Statement::Return(root_item);
 
     let mut file = File::create(output_path)?;

src/commands/sync.rs

@@ -15,7 +15,7 @@ use crate::{
     auth_cookie::get_auth_cookie,
     codegen::perform_codegen,
     data::{Config, ConfigError, ImageSlice, InputManifest, Manifest, ManifestError, SyncInput},
-    dpi_scale::dpi_scale_for_path,
+    dpi_scale,
     image::Image,
     options::{GlobalOptions, SyncOptions, SyncTarget},
     roblox_web_api::{RobloxApiClient, RobloxApiError},
@@ -241,6 +241,8 @@ impl SyncSession {
                     let name = AssetName::from_paths(config_path, &path);
                     log::trace!("Found input {}", name);
 
+                    let path_info = dpi_scale::extract_path_info(&path);
+
                     let contents = fs::read(&path)?;
                     let hash = generate_asset_hash(&contents);
 
@@ -255,8 +257,10 @@ impl SyncSession {
                         name.clone(),
                         SyncInput {
                             name,
+                            stem_name: path_info.file_stem,
                             path,
                             config: input_config.clone(),
+                            dpi_scale: path_info.dpi_scale,
                             contents,
                             hash,
                             id,
@@ -291,7 +295,7 @@ impl SyncSession {
 
             let kind = InputKind {
                 packable: input.config.packable,
-                dpi_scale: dpi_scale_for_path(&input.path),
+                dpi_scale: input.dpi_scale,
             };
 
             let input_group = compatible_input_groups.entry(kind).or_insert_with(Vec::new);
@@ -422,7 +426,7 @@ impl SyncSession {
         let hash = generate_asset_hash(&encoded_image);
 
         let upload_data = UploadInfo {
-            name: AssetName::spritesheet(),
+            name: "spritesheet".to_owned(),
             contents: encoded_image,
             hash: hash.clone(),
         };
@@ -448,7 +452,7 @@ impl SyncSession {
         let input = self.inputs.get_mut(input_name).unwrap();
 
         let upload_data = UploadInfo {
-            name: input_name.clone(),
+            name: input.stem_name.clone(),
             contents: input.contents.clone(),
             hash: input.hash.clone(),
         };

src/data/sync.rs

@@ -11,14 +11,22 @@ use crate::{
 /// results of network I/O, and from the previous Tarmac manifest file.
 #[derive(Debug)]
 pub struct SyncInput {
+    /// A unique name for this asset in the project.
     pub name: AssetName,
 
+    /// A non-unique name for this asset, excluding file extension and DPI scale
+    /// identifier, if present.
+    pub stem_name: String,
+
     /// The path on disk to the file this input originated from.
     pub path: PathBuf,
 
     /// The configuration that applied to this input when it was discovered.
     pub config: InputConfig,
 
+    /// The DPI scale of this input, if it makes sense for this input type.
+    pub dpi_scale: u32,
+
     /// The contents of the file this input originated from.
     pub contents: Vec<u8>,